The present invention relates a wing arrangement for an aircraft comprising a wing having a base section having a first end portion and an opposite second end portion, wherein the first end portion is adapted to be secured to the fuselage of an aircraft, and a tip section having a third end portion and an opposite fourth end portion, wherein the third end portion is pivotably connected to the second end portion such that the tip section is pivotable about a pivot axis between a deployed position and a stowed position in which the spanwise length of the wing is smaller than in the deployed position.
The aspect ratio, i.e. the ratio of span to chord, of an aircraft wing is one factor influencing the efficiency of the aircraft during flight. Generally, an increase of the aspect ratio is associated with an increased efficiency during steady flight. Therefore, an increase of the wingspan of an aircraft is one factor to take into consideration when seeking to reduce fuel consumption. However, when elongating the wing of an existing family of aircraft, it may become necessary to adapt the aircraft family specific infrastructure, and airport fees may increase.
One possibility to increase the wingspan without having to adapt the aircraft family specific infrastructure and having to deal with increased airport fees, or to reduce airport fees for existing aircraft is to provide for a foldable wing construction which allows to pivotably move an outboard end portion of the wing between a deployed position, in which the wing has its normal flight configuration, and a stowed position, in which the wing has a folded configuration and the wingspan is decreased as compared to the deployed position.
The present invention may be configured to provide a wing arrangement having a foldable wing which is safe and reliable in operation and has at the same time of a simple construction.
A wing arrangement for an aircraft is disclosed herein in which the wing arrangement comprises a wing having a base section and a tip section.
The base section has a first end portion, which is adapted to be secured to the fuselage of an aircraft, and an opposite second end portion. Thus, when the wing is mounted to a fuselage of an aircraft at its first end portion the second end portion of the base section is remote from the fuselage, i.e., a terminal end of the first end portion constitutes the inboard end of the base section and of the entire wing and an opposite terminal end of the second end portion constitutes the outboard end of the base section.
The tip section has a third end portion and an opposite fourth end portion. The third end portion is pivotably connected to the second end portion such that the tip section is pivotable about a pivot axis between a deployed position and a stowed position in which the spanwise length of the wing is smaller than in the deployed position. In other words, when two of the wings are mounted to opposite sides of a fuselage of an aircraft, the length of the shortest straight line between the outermost wingtips of the two wings is larger—and preferably maximized—in the deployed position than in the stowed position, i.e., the length of the wing measured along the y-axis or pitch axis of the aircraft is larger—and preferably maximized—in the deployed position than in the stowed position. In particular, the distance between the first end portion and the fourth end portion may be larger—and preferably maximized—in the deployed position than in the stowed position.
Thus, when the wing is mounted to a fuselage of an aircraft at its first end portion, and at least in the deployed position of the tip section, the third end portion of the tip section is spaced from the fuselage by the base section and the fourth end portion is the outermost portion of the wing, i.e., a terminal end of the third end portion constitutes the inboard end of the tip section and an opposite terminal end of the fourth end portion constitutes the outboard end of the tip section and of the entire wing.
It is to be noted that, in case the wing includes a wing tip device, the tip section may be identical to the wing tip device, but the tip section may comprise the wing tip device and additionally a further portion of the wing at the inboard side of the wing tip device. In this regard, in the usual manner wing tip devices are understood as devices or wing sections installed at the outermost end of a wing and being adapted to increase the effective aspect ratio of a wing without materially increasing the wingspan and to reduce drag by partially recovering the energy of tip vortices.
The wing arrangement further comprises an actuating arrangement.
The actuating arrangement comprises a linear hydraulic actuator, which, in the usual manner, comprises a cylinder defining a cylinder chamber and a piston movably arranged in the cylinder chamber and sealingly dividing the cylinder chamber into a first chamber section and a second chamber section. The sizes or volumes of the chamber sections change upon movement of the piston. When the pressure inside the first chamber section is higher than the pressure inside the second chamber section the piston moves to increase the volume of the first chamber section and to decrease the volume of the second chamber portion, and vice versa. The chamber is preferably elongate and straight, such as cylindrical, and the piston is movable along a longitudinal axis of the chamber. Preferably a piston rod is coupled to the piston and moves together with the piston. Preferably, the linear hydraulic actuator may comprise only a single cylinder and a single piston and preferably also only a single piston rod.
The linear hydraulic actuator is coupled between the base section and the tip section such that the linear hydraulic actuator is operable to selectively move the tip section between the deployed position and the stowed position. In the usual manner this is effected by movement of the piston, which is in turn effected by selectively changing the hydraulic pressure inside the first and second chamber sections, as described above and as will also be explained further below. For example, the cylinder may be coupled to one of the base section and the tip section and a piston rod of the linear hydraulic actuator may be coupled to the other one of the base section and the tip section. The deployed position and the stowed position may be defined by the linear hydraulic actuator alone, but are preferably defined by corresponding end stops lone or in combination with the linear hydraulic actuator.
The actuating arrangement further comprises a first hydraulic connection portion which is connected to the actuator such that it is in fluid communication with the first chamber section. The first hydraulic connection portion may preferably be a first hydraulic line or comprise a first hydraulic line, possibly together with a first hydraulic fluid terminal of the cylinder in fluid communication with the first chamber section, but may also merely be constituted by such first hydraulic fluid terminal. In any case, in other words, pressurized hydraulic fluid is deliverable through the first hydraulic connection portion into the first chamber section, i.e. into the cylinder chamber on a first side of the piston, independent of the position of the piston. If the supply of pressurized hydraulic fluid into the first chamber section is effected in such a way that the hydraulic pressure is higher in the first chamber section than in the second chamber section, the piston is moved in the above-described way, and for example such that a hydraulic force is applied to the actuator to move the tip section towards the deployed position.
The actuating arrangement also comprises a second hydraulic connection portion which is connected to the actuator such that it is in fluid communication with the second chamber section. Similar to the first hydraulic connection portion, the second hydraulic connection portion may preferably be a second hydraulic line or comprise a second hydraulic line, possibly together with a second hydraulic fluid terminal of the cylinder in fluid communication with the second chamber section, but may also merely be constituted by such second hydraulic fluid terminal. In any case, in other words, pressurized hydraulic fluid is deliverable through the second hydraulic connection portion into the second chamber section, i.e. into the cylinder chamber on a second side of the piston opposite the above-mentioned first side, independent of the position of the piston. If the supply of pressurized hydraulic fluid into the second chamber section is effected in such a way that the hydraulic pressure is higher in the second chamber section than in the first chamber section, the piston is moved in the above-described way, and for example such that a hydraulic force is applied to the actuator to move the tip section towards the stowed position.
Moreover, the actuating arrangement comprises a first hydraulic subsystem and a second hydraulic subsystem, which together with the first and second hydraulic connection portions form a part of or constitute a hydraulic system for hydraulically operating the linear hydraulic actuator. Each of the first and second hydraulic subsystems is connected to and branches off both of the first and second hydraulic connection portions. Further, each of the first and second hydraulic subsystems is operable to supply pressurized hydraulic fluid—and thus provide hydraulic pressure—to the first and second hydraulic connection portions. Thus, in other words, in the usual manner, each of the first and second hydraulic subsystems is operable to conduct or force pressurized hydraulic fluid into a selected one of the first and second hydraulic connection portions—and thereby into the respective chamber section—and to receive or extract pressurized hydraulic fluid from the other one of the first and second hydraulic connection portions—and thereby from the respective chamber section.
The wing arrangement also comprises a first shut-off valve—or separation valve—which is located between the first hydraulic subsystem and both of the first and second hydraulic connection portions. Thus, the first shut-off valve is also located between the first hydraulic subsystem and the second hydraulic subsystem. The first shut-off valve is operable to selectively separate the first hydraulic subsystem from the first and second hydraulic connection portions and, thus, also from the second subsystem and from the linear hydraulic actuator.
The first hydraulic subsystem comprises a first hydraulic supply including a first connector assembly adapted to be connected to a first hydraulic system of an aircraft, which first hydraulic system is operable to supply a plurality of consumers of the aircraft with pressurized hydraulic fluid, i.e. hydraulic pressure. Thus, the first hydraulic subsystem is adapted to be connected to an external source of pressurized hydraulic fluid, i.e., to an external hydraulic power supply.
The second hydraulic subsystem comprises a motor, which may be a fixed displacement or a variable displacement motor, and a pump, which may be a fixed displacement or a variable displacement pump. The motor is coupled via a motor output shaft to the pump such that it is operable to drive the pump to pump hydraulic fluid contained in the second hydraulic subsystem to the first and second hydraulic connection portions to supply pressurized hydraulic fluid to the first and second hydraulic connection portions, as already described in detail above.
The above-described wing arrangement is of a simple construction and is nevertheless capable of providing for reliable redundancy for the operation of the linear hydraulic actuator, because each of the first and second hydraulic subsystems may be preferably constructed to be individually capable of operating the linear hydraulic actuator. Further, upon construction the wing arrangement can be configured in a very flexible manner.
For example, it can be configured for a first mode of operation, in which the linear hydraulic actuator is normally operated using only the first hydraulic subsystem while the pump of the second hydraulic subsystem is not operating. Then, in case of a failure of the first hydraulic subsystem the linear hydraulic actuator is operated using only the second hydraulic subsystem by operating the pump in the above-described manner, while the first hydraulic subsystem is separated from the second hydraulic subsystem and from the linear hydraulic actuator by the first shut-off valve. In this first mode of operation, the second hydraulic subsystem is normally passive, so that it may be designated as an active/passive mode, and each of the first and second hydraulic subsystems are preferably adapted to operate the linear hydraulic actuator with the same operating characteristics, such as, e.g., speed of movement between the deployed and stowed positions. Such active/passive mode has the advantage of a reduced system complexity required for control and monitoring, because it is easier to detect failure in the respective subsystem.
Alternatively or additionally the wing arrangement can be configured for a second mode of operation, in which the linear hydraulic actuator is normally operated using both the first hydraulic subsystem and the second hydraulic subsystem, i.e. the second hydraulic subsystem is operated by operating the pump in the above-described manner while at the same time the first hydraulic subsystem is operated and in fluid communication with the linear hydraulic actuator. Then, in case of a failure of one of the two hydraulic subsystems the linear hydraulic actuator is operated using only the other one of the two hydraulic subsystems, while the one of the two hydraulic subsystems is separated from the other one of the two hydraulic subsystems and from the linear hydraulic actuator by the first shut-off valve or by a similar shut-off valve for the second hydraulic subsystem, as will be explained in more detail below. In this second mode of operation, both the first and the second hydraulic subsystem is normally active, so that it may be designated as an active/active mode, and it is possible to reduce the dimensions or power requirements of the first and second hydraulic subsystems, and therefore also the total weight of the wing arrangement, as long as it is possible to operate the linear hydraulic actuator with each of the two hydraulic subsystems alone, albeit with lower operating characteristics, such as, e.g., speed of movement between the deployed and stowed positions.
In an embodiment, the linear hydraulic actuator is the only linear hydraulic actuator, and preferably the only actuator, coupled between the base section and the tip section and operable to move the tip section between the deployed and stowed positions. This advantageously takes into account that the available space in the region of the second and third end portions is typically very limited, so that it may be difficult to find an arrangement including multiple actuators.
In an embodiment, the pivot axis is oriented in a direction extending between a first edge and a second edge of the wing opposite to each other in a chord direction of the wing, and preferably in a or the local chord direction. Thus, when moving the tip section from the deployed position into the stowed position, the tip section is pivoted downwardly or, preferably, upwardly with respect to the base section. This pivoting movement is particularly simple to implement utilizing a linear hydraulic actuator.
In an embodiment, each of the first and second hydraulic subsystems is adapted to effect movement of the tip section between the deployed and stowed positions independent of the other one of the first and second subsystems, i.e., each of the two subsystems constitutes an independent hydraulic power supply and hydraulic system adapted to actuate the linear hydraulic actuator individually when the other hydraulic power supply is not utilized or available. This provides for full redundancy, as already noted above and as described above in an exemplary manner with respect to the two modes of operation designated as active/passive and active/active.
In an embodiment, the second hydraulic subsystem comprises a second hydraulic supply including a second connector assembly separate from the first connector assembly and adapted to be connected to a second hydraulic system of an aircraft, which second hydraulic system is operable to supply a plurality of consumers of the aircraft with pressurized hydraulic fluid, i.e. hydraulic pressure. Thus, in this embodiment, similar to the first hydraulic subsystem the second hydraulic subsystem is likewise adapted to be connected to an external source of pressurized hydraulic fluid, i.e., to an external hydraulic power supply. In this embodiment the motor is a hydraulic motor connected to the second hydraulic supply and operable to be driven by pressurized hydraulic fluid supplied by the second hydraulic supply. The part of the second hydraulic subsystem, in which hydraulic fluid is pumped by the pump, acts as a local independent hydraulic system after closing the first shut-off valve, and the first and second hydraulic power supplies are advantageously separated from each other by the pump and motor arrangement.
In this embodiment, there is preferably also a pressure control arrangement adapted to provide for a predetermined minimum hydraulic pressure and to prevent occurrence of negative pressure. For example, to achieve these effects the second hydraulic subsystem may preferably comprise a hydraulic accumulator, which acts as a hydraulic reservoir adapted to store hydraulic fluid—i.e. generally a hydraulic reservoir adapted to provide pressurized hydraulic fluid with a predetermined minimum pressure—, and a pressure relief valve connectable or arranged between the hydraulic accumulator and the suction side of the hydraulic pump. The pressure relief valve is normally closed and adapted to open when a predetermined hydraulic pressure is exceeded to thereby connect the suction side of the pump to the hydraulic accumulator. This allows the hydraulic accumulator to assist the pump in case of insufficient supply of pressurized hydraulic fluid at the suction side and to receive pressurized hydraulic fluid from the suction side if the hydraulic pressure at the suction side is too high, and thereby allows the hydraulic accumulator to maintain the return pressure or a particular hydraulic pressure at the suction side of the hydraulic pump. In this embodiment the hydraulic accumulator is connected via separate check valves to the first and second hydraulic connection portions in such a manner that the hydraulic accumulator is operable to serve as a source of pressurized hydraulic fluid, i.e., a separate hydraulic pressure source, in case the hydraulic pressure at the suction side of the hydraulic pump is lower than the hydraulic pressure in the hydraulic accumulator. This may be achieved by suitably configuring and arranging the check valves. It is to be noted that the hydraulic accumulator may be filled with pressurized hydraulic fluid during maintenance or preparation of the respective aircraft, or that the hydraulic accumulator is connected via a check valve to the first hydraulic subsystem or, if present, the first hydraulic supply, so that it is filled with pressurized hydraulic fluid during normal operation of the two subsystems.
This embodiment provides the advantage that the two hydraulic subsystems are configured and constructed in the same manner.
In an alternative embodiment the motor is an electric motor, so that different from the preceding embodiment no external source of pressurized hydraulic fluid is necessary for drive the motor. The pump is operable to pump hydraulic fluid contained in the part of the second hydraulic subsystem, in which the hydraulic fluid is pumped by the pump, to the first and second hydraulic connection portions in the manner described in detail above, i.e., to a selected one of the first and second hydraulic connection portions, when driven by the motor. The second hydraulic subsystem, and in particular the part of the second hydraulic subsystem in which hydraulic fluid is pumped by the pump, again acts as a local independent hydraulic system after closing the first shut-off valve. Providing the motor as an electric motor may be advantageous if it is not possible or difficult, for example due to space constraints, to provide two independent hydraulic power supplies or hydraulic subsystems with sufficient supply characteristics at the tip section. Providing the motor as an electric motor also provides the advantage that the tip section can still be moved and the wing arrangement can still be operated in the manner described herein if hydraulic power is not available, such as, e.g., during maintenance.
In this embodiment, there is again preferably also a pressure control arrangement adapted to provide for a predetermined minimum hydraulic pressure and to prevent occurrence of negative pressure. For example, to achieve these effects the second hydraulic subsystem may preferably comprise a hydraulic accumulator, which acts as a hydraulic reservoir adapted to store hydraulic fluid, i.e. generally a hydraulic reservoir adapted to provide pressurized hydraulic fluid with a predetermined minimum pressure. The hydraulic accumulator is connectable to the suction side of the pump via a separation valve. The separation valve is normally closed and is controlled to open when the second hydraulic subsystem is active, i.e. the pump is driven by the motor, to thereby connect the suction side of the pump to the hydraulic accumulator. This allows the hydraulic accumulator to assist the pump in case of insufficient supply of pressurized hydraulic fluid at the suction side and to receive pressurized hydraulic fluid from the suction side if the hydraulic pressure at the suction side is too high, and thereby allows the hydraulic accumulator to maintain the return pressure or a particular hydraulic pressure at the suction side of the hydraulic pump.
If the hydraulic accumulator is provided for in this embodiment, the hydraulic accumulator is preferably connected to the first hydraulic supply via a check valve, such that hydraulic fluid is provided to the hydraulic reservoir by the first hydraulic system if the hydraulic pressure provided by the first hydraulic system is higher than the pressure inside the hydraulic reservoir, so that it is filled with pressurized hydraulic fluid during normal operation of the two subsystems. Of course, it is in principle also possible that the hydraulic reservoir is not connected and not connectable to the first hydraulic supply, but to require it to be filled with pressurized hydraulic fluid during maintenance or preparation of the respective aircraft.
In an embodiment, the wing arrangement further comprises a second shut-off valve—or separation valve—which is located between the second hydraulic subsystem and both of the first and second hydraulic connection portions. Thus, the second shut-off valve is also located between the second hydraulic subsystem and the first hydraulic subsystem. The second shut-off valve is operable to selectively separate the second hydraulic subsystem from the first and second hydraulic connection portions and, thus, also from the first subsystem and from the linear hydraulic actuator. As an alternative to the second shut-off valve or in addition to the second shut-off valve a clutch may be provided between the motor shaft and the pump. If the second shut-off valve is dispensed with, the pump is preferably provided with a brake, which is adapted to brake the pump when the second hydraulic subsystem is not utilized. The latter arrangement may be advantageously used, in particular in the case of an active/passive mode of operation. In case the clutch is provided in addition to the second shut-off valve the brake is not necessary.
In an embodiment, the pump and the motor are bidirectional such that the hydraulic fluid contained in the second hydraulic subsystem is pumped to the first hydraulic connection portion or to the second hydraulic connection portion depending on the direction in which the motor is driven by the pump. Alternatively, the pump and the motor may be unidirectional and the second hydraulic subsystem may then further include a selection valve which can be selectively switched between a first position in which the hydraulic fluid contained in the second hydraulic subsystem is pumped to first hydraulic connection portion and a second position in which the hydraulic fluid contained in the second hydraulic subsystem is pumped to second hydraulic connection portion.
In an embodiment, the wing arrangement further comprises a latching device or arrangement, which has one or more latching elements which are selectively movable between a latching position and a release position. The configuration and arrangement of the one or more latching elements are such that when the tip section is in the deployed position and the one or more latching elements are moved from the release position to the latching position the one or more latching elements engage one of the tip section and the base section and thereby prevent the tip section from moving out of the deployed position. A support of the latching device, with respect to which support the one or more latching elements are movable, is then preferably fixedly secured to the other one of the tip section and the base section. Further, when the tip section is in the deployed position and the one or more latching elements are moved from the latching position to the release position the tip section or the base section is able to disengage from the one or more latching elements, so that the tip section is able to move from the deployed position into the stowed position.
The wing arrangement then also comprises one or more first latching actuators, which are preferably hydraulic but may also be electric, and one or more second latching actuators, which are preferably hydraulic but may also be electric. The one or more first latching actuators are operable to move the one or more latching elements from the latching position into the release position independent of the one or more second latching actuators, and, conversely, the one or more second latching actuators are operable to move the one or more latching elements from the latching position into the release position independent of the one or more first latching actuators. The one or more first latching actuators may be one or more first hydraulic latching actuators and the one or more second latching actuators are one or more second hydraulic latching actuators, the one or more first latching actuators are connected to and operable by the first hydraulic subsystem, and the one or more second latching actuators are connected to and operable by the second hydraulic subsystem, thereby providing for full redundancy in the operation of the latching device. In the case of electrically powered first and second latching actuators the one or more first latching actuators are driven by first electric drive means and the one or more second latching actuators are driven by separate second electric drive means, thereby again providing for full redundancy in the operation of the latching device.
In this embodiment, the one or more first latching actuators are operable to move the one or more latching elements from the release position into the latching position independent of the one or more second latching actuators, and, conversely, the one or more second latching actuators are operable to move the one or more latching elements from the release position into the latching position independent of the one or more first latching actuators. Alternatively or additionally if the latching device includes at least one biasing device or arrangement, which may be or comprise one or more springs and at least one spring for each latching element. The biasing device is arranged and adapted to bias the at least one latching element into the latching position. The biasing device may assist the one or more first and second latching actuators in moving the one or more latching elements from the release position into the latching position, e.g. in order to preposition them, or they may be the sole means for effecting this movement. In the latter case, the latching elements are normally in the latching position, and active power, preferably active hydraulic power, must be used to move them into the release position. It should be noted that it is also possible that the biasing device includes a dead-center position, on both sides of which it biases the one or more latching elements into a different one of the release position and the latching position. Then, the one or more first latching actuators as well as, independently, the one or more second latching actuators may be operable to move the one or more latching elements towards and over the dead-center position of the biasing device, and the biasing device may then effect the final movement into the release position or the latching position, as the case may be, either alone or together with the one or more first latching actuators or the one or more second latching actuators.
In the above embodiments comprising a latching device or arrangement, it is possible that the biasing device, if provided, exerts sufficient force on the one or more latching elements in the latching position to securely retain them in the latching position against forces acting on them during operation of an aircraft to which the wing arrangement is attached, such as forces from acceleration from runway bumps, braking and turns, wind loads from taxiing, maximum gusts and jet blasts. If the biasing device or arrangement does not provide sufficient force or is not present, the wing arrangement may also comprise a locking device having one or more locking elements which are selectively movable between a locking position and an enabling position. The configuration and arrangement of the one or more locking elements are such that when the one or more latching elements are in the latching position and the one or more locking elements are moved from the enabling position to the locking position the one or more locking elements engage the one or more latching elements and prevent the one or more latching elements from moving out of the latching position. Further, when the one or more latching elements are in the latching position and the one or more locking elements are moved from the locking position to the enabling position the one or more latching elements are able to move from the latching position into the release position.
The wing arrangement then also comprises one or more first locking actuators, which are preferably hydraulic but may also be electric, and one or more second locking actuators, which are preferably hydraulic but may also be electric. The one or more first locking actuators are operable to move the one or more locking elements from the locking position into the enabling position—and preferably also from the enabling position into the locking position—independent of the one or more second locking actuators, and, conversely, the one or more second locking actuators are operable to move the one or more locking elements from the locking position into the enabling position—and preferably also from the enabling position into the locking position—independent of the one or more first locking actuators. In a case in which the one or more first locking actuators are one or more first hydraulic locking actuators and the one or more second locking actuators are one or more second locking latching actuators, the one or more first hydraulic locking actuators are connected to and operable by the first hydraulic subsystem, and the one or more second hydraulic locking actuators are connected to and operable by the second hydraulic subsystem, thereby providing for full redundancy in the operation of the locking device. In the case of electrically powered first and second locking actuators the one or more first locking actuators are driven by first electric drive means and the one or more second locking actuators are driven by separate second electric drive means, thereby again providing for full redundancy in the operation of the locking device.
Similar to the case of the latching device, the locking device may likewise comprise at least one biasing device or arrangement, which may preferably be or comprise one or more springs and preferably at least one spring for each locking element. This locking element biasing device is arranged and adapted to bias the at least one locking element into the locking position. The locking element biasing device may assist the one or more first and second locking actuators in moving the one or more locking elements from the enabling position into the locking position, e.g. in order to preposition them, or they may be the sole means for effecting this movement. In the latter case, the locking elements are normally in the locking position, and active power, preferably active hydraulic power, must be used to move them into the enabling position. It should be noted that it is also possible that the locking element biasing device includes a dead-center position, on both sides of which it biases the one or more locking elements into a different one of the enabling position and the locking position. Then, the one or more first locking actuators as well as, independently, the one or more second locking actuators may be operable to move the one or more locking elements towards and over the dead-center position of the locking element biasing device, and the locking element biasing device may then effect the final movement into the enabling position or the locking position, as the case may be, either alone or together with the one or more first locking actuators or the one or more second locking actuators.
In any if the above embodiments comprising a latching device or arrangement, and possibly also a separate locking device or arrangement, it is possible that the same latching device, and possibly also the same locking device, is also configured and operable in the same manner such that when the tip section is in the stowed position and the one or more latching elements are moved from the release position to the latching position or a different latching position the one or more latching elements engage one of the tip section and the base section and thereby prevent the tip section from moving out of the stowed position, and, when the tip section is in the stowed position and the one or more latching elements are moved from the latching position or the different latching position to the release position the tip section or the base section is able to disengage from the one or more latching elements, so that the tip section is able to move from the stowed position into the deployed position. In this case, the one or more latching elements preferable engage the tip section or the base section, as the case may be, at a different location or portion than in the case of latching the tip section in the deployed position.
Alternatively it is also possible that a separate latching device or arrangement, which has one or more latching elements which are selectively movable between a latching position and a release position and may otherwise be configured and operating in the same manner as described above, is provided as part of the wing arrangement or as a unit or arrangement external to and separate from the wing arrangement and possibly also external to and separate from the aircraft to which the wing arrangement is secured. In any case, such a separate latching device or arrangement, which may in the same manner also include a separate locking device or arrangement, may be designated as ground latching device or arrangement. Whether external to the wing arrangement and aircraft or not it may comprise two hydraulic terminals to which an external hydraulic power source may be connected when the aircraft is on the ground or to which, preferably, the first and second hydraulic subsystems or first and second hydraulic systems of the aircraft are connected in order to operate the first and second latching actuators, and possibly the first and second locking actuators. In any case, the tip section then preferably comprises one or more engagement portions for the separate latching device or arrangement, which engagement portions are engageable by the latching elements in the stowed position of the tip section.
The wing arrangement preferably comprises two separate control units or computers or, preferably, terminals for connection to two separate control units or computers, which are each adapted to control the operation of the wing arrangement described above for each of the embodiments, such as moving the tip section between the deployed and stowed positions, latching and unlatching the tip section and locking and unlocking the tip section. In case the control units are provided as part of the wing arrangement, the wing arrangement preferably comprises a terminal for connection to an actuating element of an aircraft, such as an actuating lever, and the two control units are then adapted to receive control commands from the actuating element and to control the operation of the wing arrangement accordingly. In particular, such an actuating element may be adapted to selectively transmit a first instruction or set of instructions and a different second instruction or set of instructions, wherein the first instruction or set of instructions effects all of the above operations for moving the tip section to the deployed position and for securely retaining it therein, and the second instruction or set of instructions effects all of the above operations for moving the tip section to the stowed position and for securely retaining it therein. Further, the wing arrangement preferably comprises a plurality of sensors which are arranged and adapted to sense the operation of the first and second hydraulic subsystems and of the linear hydraulic actuators, such as the position and/or operation of the various actuators mentioned above, and to provide corresponding sensor signals. The sensors are then connected to the two control units or to sensor terminals for connection to two external control units, and the control units are adapted to process the sensor signals and to control the wing arrangement depending on the sensor signals, for example by switching from the first hydraulic subsystem to the second hydraulic subsystem in the manner described above in case the sensor signals indicate failure of the first hydraulic subsystem.
The first and second hydraulic subsystems and, if present, the latching arrangement and the locking arrangement may preferably and advantageously be located outside a wing box of the wing, i.e., forward of a front spar and/or rearward of a rear spar, and in particular a wing box of the base section. By contrast, the linear hydraulic actuator and, if present, the ground latching device or arrangement are preferably located inside the wing box of wing, and in particular the wing box of the base section.
The wing arrangement according to any of the above-described embodiments may be part of an aircraft. The aircraft further comprises a fuselage, wherein the first end portion of the base section is attached to the fuselage and the base section is arranged between the fuselage and the tip section, and a first hydraulic system, which first hydraulic system is operable to supply a plurality of consumers of the aircraft with pressurized hydraulic fluid and which is connected to the first connector assembly. In embodiments of the wing arrangement also comprising the second connector assembly, the aircraft preferably further comprises a second hydraulic system, which second hydraulic system is operable to supply a plurality of consumers of the aircraft with pressurized hydraulic fluid and which is connected to the second connector assembly. In these cases the first hydraulic system is preferably separate from the second hydraulic system, i.e. the second hydraulic system is independent or not in fluid communication with the first hydraulic system.
The aircraft preferably comprises the two control units or computers and the actuating element mentioned above within the fuselage of the aircraft.
It is to be noted that although two hydraulic subsystems have been described above for actuating the linear hydraulic actuator, it is in principle also conceivable to replace the second hydraulic subsystem by electric drive means for moving the linear hydraulic actuator—as well as the latching actuators and the locking actuators, if present—or the tip section as such—and the latching elements and locking elements, if present.